Influence Of Thermal Gradient On Mechanical Properties In Fused Deposition Modelling (Fdm) Additive Manufacturing

Fused Deposition Modeling (FDM) is a technique that constructs functional parts by extruding thermoplastic filaments layer by layer. The interplay between thermal dynamics and their subsequent effects on mechanical properties remains a field necessitating further exploration. This study introduced ongoing research focused on unraveling the connection between the thermal gradients in the FDM printing process and the resulting mechanical attributes. The primary objective was to increase quality and functionality of 3D printed components. In pursuit of this objective, a series of carefully planned experiments were devised to systematically vary FDM parameters, including print speed, layer thickness, and nozzle temperature. Through parameter manipulation, a spectrum of thermal gradients during the printing procedure we created. To assess the mechanical properties, a commercial FDM 3D printer was used to fabricate tensile specimens conforming to the ASTM D638 standard, a test method for quantifying the tensile properties of plastics. To capture the thermal gradient occurring during printing process, a high-resolution FLIR thermal camera was positioned closely to observe the area where freshly molten material was deposited to obtain temperature measurements. After the sample was printed, it was mechanically tested using Instron 5582 for tensile testing following the ASTM D638 standard, entailing the application of a uniaxial load until the specimen reached the point of fracture. Mechanical properties such as yield strength, ultimate tensile strength, and elongation at break, which offered fundamental insights into the material\u27s strength, ductility, and performance under tensile stress. The experimental results obtained through these tests were analyzed to unveil potential correlations between the thermal gradient and mechanical properties. Undersatnding the interrelationship, gained a deeper understanding of the underlying thermal relationship in the FDM 3D printing process and their impact on the mechanical behavior of printed objects. The findings derived from this research contributed to comprehension of thermal effects in FDM 3D printing and their ramifications for mechanical performance. These insights hold promise for optimizing the printing process, therefore elevating the quality and functionality of 3D-printed components. Industries reliant on FDM technology, including aerospace, automotive, and medical sectors, stand to gain from improved process control, ultimately enhancing part reliability and performance. Index Terms – 3D printing, astm d638 standard, correlation analysis, fused deposition modeling (fdm), mechanical properties, parameter manipulation, performance under tensile stress, thermal dynamics, thermal gradients, yield strengt

Visual Propaganda and Extremism in the Online Environment

Visual images have been a central component of propaganda for as long as propaganda has been produced. But recent developments in communication and information technologies have given terrorist and extremist groups options and abilities they never would have been able to come close to even 5 or 10 years ago. There are terrorist groups who, with very little initial investment, are making videos that are coming so close to the quality of BBC or CNN broadcasts that the difference is meaningless, and with access to the web they have instantaneous access to a global audience. Given the broad social science consensus on the power of visual images relative to that of words, the strategic implications of these groups’ sophistication in the use of images in the online environment is carefully considered in a variety of contexts by the authors in this collection.https://press.armywarcollege.edu/monographs/1942/thumbnail.jp

Willingness To Donate Blood During the Summer

Introduction. Each year donation rates fall in the summer months straining blood banks’ capacities to meet local demands. In hopes of identifying factors to increase summer donations, our study investigated donor reported barriers which influence summer donations habits.Methods. An anonymous 16 question survey investigating various donation factors was administered across multiple American Red Cross (ARC) donation centers in Vermont. Questions addressed donor demographics, frequency of blood donation, preference in appointment making modalities including smartphone app use, summer travel habits, willingness to donate during vacation, and factors that deter donors from donating on vacation.Results. A total of 292 surveys were received. Survey respondents across multiple demographic groups cited similar barriers to summer donation, namely “Too busy” (27.5 %) and “Traveling is a time for me to relax.” (30.6 %). Of the respondents who travel in the summer, very few reported donating while traveling (3.4 %). Summer donation rates between summertime travelers (36.5 %) and non-travelers (36.4 %) were essentially equivalent. The most preferred methods of scheduling appointments were via ARC website (45.6 %) and phone (28.4%). Willingness to use the ARC app was highest among respondents ages of 18 to 34 (45-55%) and lowest among ages 55 and older (13-15%). Of respondents with no prior knowledge of summer seasonal shortages (22 %), 2/3rds indicated newfound motivation to donate.Conclusion. Regardless of travel, increasing awareness of summer shortages may increase summer donations. Use of donor websites and smartphone apps may be instrumented as part of recruitment efforts.https://scholarworks.uvm.edu/comphp_gallery/1239/thumbnail.jp

Using next generation matrices to estimate the proportion of infections that are not detected in an outbreak

Contact tracing, where exposed individuals are followed up to break ongoing transmission chains, is a key pillar of outbreak response for infectious disease outbreaks. Unfortunately, these systems are not fully effective, and infections can still go undetected as people may not remember all their contacts or contacts may not be traced successfully. A large proportion of undetected infections suggests poor contact tracing and surveillance systems, which could be a potential area of improvement for a disease response. In this paper, we present a method for estimating the proportion of infections that are not detected during an outbreak. Our method uses next generation matrices that are parameterized by linked contact tracing data and case line-lists. We validate the method using simulated data from an individual-based model and then investigate two case studies: the proportion of undetected infections in the SARS-CoV-2 outbreak in New Zealand during 2020 and the Ebola epidemic in Guinea during 2014. We estimate that only 5.26% of SARS-CoV-2 infections were not detected in New Zealand during 2020 (95% credible interval: 0.243 – 16.0%) if 80% of contacts were under active surveillance but depending on assumptions about the ratio of contacts not under active surveillance versus contacts under active surveillance 39.0% or 37.7% of Ebola infections were not detected in Guinea (95% credible intervals: 1.69 – 87.0% or 1.70 – 80.9%)

Regulation of phosphorylase kinase by low concentrations of Ca ions upon muscle contraction: the connection between metabolism and muscle contraction and the connection between muscle physiology and Ca-dependent signal transduction

It had long been one of the crucial questions in muscle physiology how glycogenolysis is regulated in connection with muscle contraction, when we found the answer to this question in the last half of the 1960s. By that time, the two principal currents of muscle physiology, namely, the metabolic flow starting from glycogen and the mechanisms of muscle contraction, had already been clarified at the molecular level thanks to our senior researchers. Thus, the final question we had to answer was how to connect these two currents. We found that low concentrations of Ca ions (10−7–10−4 M) released from the sarcoplasmic reticulum for the regulation of muscle contraction simultaneously reversibly activate phosphorylase kinase, the enzyme regulating glycogenolysis. Moreover, we found that adenosine 3′,5′-monophosphate (cyclic AMP), which is already known to activate muscle phosphorylase kinase, is not effective in the absence of such concentrations of Ca ions. Thus, cyclic AMP is not effective by itself alone and only modifies the activation process in the presence of Ca ions (at that time, cyclic AMP-dependent protein kinase had not yet been identified). After a while, it turned out that our works have not only provided the solution to the above problem on muscle physiology, but have also been considered as the first report of Ca-dependent protein phosphorylation, which is one of the central problems in current cell biology. Phosphorylase kinase is the first protein kinase to phosphorylate a protein resulting in the change in the function of the phosphorylated protein, as shown by Krebs and Fischer. Our works further showed that this protein kinase is regulated in a Ca-dependent manner. Accordingly, our works introduced the concept of low concentrations of Ca ions, which were first identified as the regulatory substance of muscle contraction, to the vast field of Ca biology including signal transduction

Epitope tag-specific differences in the detection of COSA-1 marked crossover sites in C. elegans spermatocytes

6 jpagesNascent crossover sites in C. elegans meiocytes can be cytologically detected using epitope-tagged versions of the pro-crossover protein COSA-1. In spermatocytes, differences exist between cytologically-detected and genetically-detected double crossover rates. Here, we examine nascent crossovers using both GFP- and OLLAS-tagged COSA-1. Similar to previous work, we find that most late pachytene spermatocytes display 5 COSA-1 foci, indicating one crossover per autosome bivalent. However, we detected more nuclei with >5 COSA-1 foci using OLLAS::COSA-1, reflecting some bivalents having 2 COSA-1 foci. These results demonstrate tag-specific differences in the detection of COSA-1 marked nascent crossovers in spermatocytes.This work was supported by the National Institutes of Health R35GM128890 to DEL, a Jane Coffin Childs Postdoctoral Fellowship and National Institutes of Health 1K99HD109505-01 to CKC, National Institutes of Health R35GM126964 to AMV, and a Stanford Dean’s Fellowship award to CJU. DEL is also a Searle Scholar and recipient of a March of Dimes Basil O’Connor Starter Scholar award. SIM imaging was performed at Stanford University Cell Sciences Imaging Core Facility, which is supported by Award Number 1S10OD01227601 from the National Center for Research Resources

Avalanche Polynomials of some Families of Graphs

We study the abelian sandpile model on different families of graphs. We introduced the avalanche polynomial which enumerates the size of the avalanches triggered by the addition of a particle on a recurrent configuration. This polynomial is calculated for several families of graphs. In the case of the complete graph, the result involves some known result on Parking function

Genome sequencing defines phylogeny and spread of methicillin-resistant Staphylococcus aureus in a high transmission setting.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial infection. Whole-genome sequencing of MRSA has been used to define phylogeny and transmission in well-resourced healthcare settings, yet the greatest burden of nosocomial infection occurs in resource-restricted settings where barriers to transmission are lower. Here, we study the flux and genetic diversity of MRSA on ward and individual patient levels in a hospital where transmission was common. We repeatedly screened all patients on two intensive care units for MRSA carriage over a 3-mo period. All MRSA belonged to multilocus sequence type 239 (ST 239). We defined the population structure and charted the spread of MRSA by sequencing 79 isolates from 46 patients and five members of staff, including the first MRSA-positive screen isolates and up to two repeat isolates where available. Phylogenetic analysis identified a flux of distinct ST 239 clades over time in each intensive care unit. In total, five main clades were identified, which varied in the carriage of plasmids encoding antiseptic and antimicrobial resistance determinants. Sequence data confirmed intra- and interwards transmission events and identified individual patients who were colonized by more than one clade. One patient on each unit was the source of numerous transmission events, and deep sampling of one of these cases demonstrated colonization with a "cloud" of related MRSA variants. The application of whole-genome sequencing and analysis provides novel insights into the transmission of MRSA in under-resourced healthcare settings and has relevance to wider global health.The authors acknowledge financial support from the UKCRC Translational Infection Research (TIR) Initiative and the Medical Research Council (Grant number G1000803), with contributions to the grant from the Biotechnology and Biological Sciences Research Council, the National Institute for Health Research on behalf of the Department of Health, and the Chief Scientist Office of the Scottish Government Health Directorate (to Professor Peacock); from Wellcome Trust grant number 098051 awarded to the Wellcome Trust Sanger Institute; and the NIHR Cambridge Biomedical Research Centre (to Professor Peacock). S.Y.C.T. is an Australian National Health and Medical Research Council Career Development Fellow (1065736)This is the final version of the article. It first appeared at http://www.genome.org/cgi/doi/10.1101/gr.174730.114